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  1. 06 Feb, 2009 3 commits
    • NeilBrown's avatar
      md: Ensure an md array never has too many devices. · de01dfad
      NeilBrown authored 
      Each different metadata format supported by md supports a
different maximum number of devices.
We really should be enforcing this maximum in the kernel, but
we aren't quite doing that properly.

We currently only enforce it at the 'hot_add' point, which is an
older interface which is not used by current userspace.

We need to also enforce it at 'add_new_disk' time for active arrays
and at 'do_md_run' time when starting a new array.

So move the test from 'hot_add' into 'bind_rdev_to_array' which is
called from both 'hot_add' and 'add_new_disk, and add a new
test in 'analyse_sbs' which is called from 'do_md_run'.

This bug (or missing feature) has been around "forever" and so
the patch is suitable for any -stable that is currently maintained.

Cc: stable@kernel.org
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      de01dfad
    • Andre Noll's avatar
      md: Fix a bug in linear.c causing which_dev() to return the wrong device. · 852c8bf4
      Andre Noll authored 
      ab5bd5cb introduced the following
bug in linear software raid for large arrays on 32 bit machines:

which_dev() computes the device holding a given sector by shifting
down the sector number to a 32 bit range, dividing by the array
spacing and looking up the resulting index in the hash table of
the array.

Because the computed index might be slightly too small, a loop at
the end of which_dev() increases the index until the given sector
actually falls into the range of the device associated with that index.

The changes of the above mentioned commit caused this loop to check
whether the _index_ rather than the sector number is small enough,
effectively bypassing the loop and thus possibly returning the wrong
device.

As reported by Simon Kirby, this leads to errors such as

	linear_make_request: Sector 2340486136 out of bounds on dev sdi: 156301312 sectors, offset 2109870464

Fix this bug by introducing a local variable for the index so that
the variable containing the passed sector is left unchanged.

Cc: stable@kernel.org
Signed-off-by: default avatarAndre Noll <maan@systemlinux.org>
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      852c8bf4
    • NeilBrown's avatar
      md: Allow read error in a single drive raid1 to be passed up. · 4706b349
      NeilBrown authored 
      If a raid1 only has a single working device and gets a read error, 
we choose to simply return that error up to the filesystem (or whatever)
rather than failing the whole array.

However the codes doesn't quite do that.  We attempt a readbalance
which allocates the same drive, so we retry the read - indefinitely. 

Instead:  If read_balance in the error case chooses the same drive that just
failed, treat it as a failure and don't retry.
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      4706b349
  3. 04 Feb, 2009 37 commits
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